(a) Field of the Invention
The present invention relates to a system and a method for measuring an inclination of a vehicle, and more particularly, to a system and a method for measuring an inclination of a vehicle, which can measure an inclination by adjusting to a driving state of a vehicle.
(b) Description of the Related Art
In general, when a vehicle is driven on an inclined surface with respect to a reference surface, the vehicle travels in an inclined state. An inclination along a driving direction of the vehicle is used for various purposes. For example, an inclination may be utilized for improving fuel efficiency and determining a shift pattern of a vehicle. Further, an inclination of a road may be utilized for preventing a vehicle from sliding upon turning on the engine. Further, an inclination of a vehicle may be used for determining a driving route of navigation, controlling a position of a vehicle, improving fuel efficiency of a vehicle, detecting real-time energy consumption of a vehicle, and the like.
The inclination may be measured by various methods, such as an atmospheric pressure sensor, an acceleration sensor, an electronic compass, and a gyro sensor, but the acceleration sensor is most commonly used.
When an inclination angle is measured by using the acceleration sensor, a signal of the acceleration sensor may be filtered using a low pass filter (LPF). An example of a method of measuring an inclination by using an acceleration sensor and a low pass filter is illustrated in FIG. 1.
Referring to FIG. 1, a signal of an acceleration sensor is monitored (e.g., received) to measure an inclination, and an acceleration of a vehicle is calculated based on the signal of the acceleration sensor. Further, to remove a high frequency component and signal noise in the sensor of the acceleration sensor, the signal of the acceleration sensor is filtered with the low pass filter.
When the signal of the acceleration sensor is filtered with the low pass filter, the inclination is calculated based on the filtered signal of the acceleration sensor, and a final inclination value is output by filtering a signal of the calculated inclination value with the low pass filter to remove a noise signal in the calculated inclination value.
However, according to the aforementioned method of measuring the inclination, the low pass filter is used to remove the high frequency component and/or the noise signal in the signal of the acceleration sensor, the following problems may be incurred.
When a gain value of the low pass filter is increased to improve performance in a vehicle speed stabilization section, a delay of a response time may be generated as illustrated in FIG. 2. When the response time is delayed, a vehicle may be controlled with a previously measured inclination value at a location having no inclination.
On the contrary, when the gain value of the low pass filter is decreased to improve response performance, the high frequency component may be reflected to the inclination, thereby reducing reliability of the measured inclination.
Further, according to the method of measuring the inclination in the related art, since a plurality of filters are used in each filtering step to obtain a stable inclination, a measured inclination value may decrease compared to an actual inclination value.
The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.